Allow the site engagement service thresholds to be varied via field trial.

chrome/browser/engagement/site_engagement_service.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_SERVICE_H_
 #define CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_SERVICE_H_
 
 #include <map>
 
 #include "base/gtest_prod_util.h"
@@ skipping 10 matching lines @@
 class GURL;
 class Profile;
 
 class SiteEngagementScore {
  public:
   // Keys used in the content settings dictionary.
   static const char* kRawScoreKey;
   static const char* kPointsAddedTodayKey;
   static const char* kLastEngagementTimeKey;
 
+  // Keys used in the variations params.
+  static const char* kEngagementParams;
+  static const char* kMaxPointsPerDayParam;
+  static const char* kNavigationPointsParam;
+  static const char* kUserInputPointsParam;
+  static const char* kDecayPeriodInDaysParam;
+  static const char* kDecayPointsParam;

[benwells, 2015/09/29 00:40:31]

Do all these keys (and the content settings keys) need to be public?

[dominickn, 2015/09/29 00:52:30]

@calamity: any thoughts on making all of these private? I believe that they're
accessed a lot in tests.

[calamity, 2015/10/01 08:41:19]

These are just the keys, not the values?

I don't think they're used in tests too much.

I support privatization of this sector.

[dominickn, 2015/10/01 09:04:22]

Done.

+
   // The maximum number of points that are allowed.
   static const double kMaxPoints;
 
   // The maximum number of points that can be accrued in one day.
-  static const double kMaxPointsPerDay;
+  static double gMaxPointsPerDay;
 
   // The number of points given for navigations.
-  static const double kNavigationPoints;
+  static double gNavigationPoints;
 
   // The number of points given for user input (indicating time-on-site).
-  static const double kUserInputPoints;
+  static double gUserInputPoints;
 
   // Decaying works by removing a portion of the score periodically. This
   // constant determines how often that happens.
-  static const int kDecayPeriodInDays;
+  static int gDecayPeriodInDays;
 
   // How much the score decays after every kDecayPeriodInDays.
-  static const double kDecayPoints;
+  static double gDecayPoints;

[calamity, 2015/10/01 08:41:19]

nit: g_decay_points and above to match majority of Chrome.

[calamity, 2015/10/06 03:52:40]

Ping?

You can do this quickly by running

sed -i 's/gDecayPoints/g_decay_points/g' `git diff --name-only @{u}`

etc

[dominickn, 2015/10/06 05:00:39]

Done.

+
+  // Update the default engagement settings via variations.
+  static void UpdateFromVariations();
 
   // The SiteEngagementService does not take ownership of |clock|. It is the
   // responsibility of the caller to make sure |clock| outlives this
   // SiteEngagementScore.
   SiteEngagementScore(base::Clock* clock,
                       const base::DictionaryValue& score_dict);
   ~SiteEngagementScore();
 
   double Score() const;
   void AddPoints(double points);
@@ skipping 95 matching lines @@
 
   Profile* profile_;
 
   // The clock used to vend times.
   base::DefaultClock clock_;
 
   DISALLOW_COPY_AND_ASSIGN(SiteEngagementService);
 };
 
 #endif  // CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_SERVICE_H_